Tractors and skid steers are common utility vehicles in the farming, construction and landscaping industries. The primary benefit of these vehicles is their great versatility and the wide variety of implements that can be attached to and used with the vehicle. After an initial investment in a tractor or skid steer, owners of these vehicles can add increased functionality by purchasing a wide variety of specialized implements including loaders, backhoes, blades, post hole diggers, forks and bale spears, to name a few. Because of the ubiquity and great versatility of tractors and skid steers, owners of these vehicles continuously seek new and improved implements to perform specialized tasks.
Grappling jaws are good examples of implements that are especially useful for performing specialized tasks. These implements are essentially large, heavy-duty jaws that can be opened and closed around material so that the material may be grasped, lifted and transported by the vehicle. Because these implements can be closed around the material or item, these implements expand the lifting and carrying capabilities of the utility vehicle.
Grappling jaws of various configurations have been developed for use with front end loaders and skid steers. In their most common form, grappling jaws have been adapted for use with the conventional loader bucket of these vehicles. For example, as shown in U.S. Pat. Nos. 5,094,581 and 5,957,650, the grappling jaw is attached to the bucket so that the jaw may be closed over the bucket to secure material being carried in the bucket. The grappling jaw is typically controlled by a hydraulic piston or multiple pistons that open and close the jaw relative to the bucket. Such grappling jaws can significantly increase the carrying capacity of the bucket and are useful for securing and controlling loose material carried in the bucket, as well as large, regularly shaped items such as hay bales.
Grappling jaws in this configuration, however, suffer many limitations. In particular, the bucket and grappling jaw combination is not well suited for highly precise grasping tasks. First, the bucket must be inserted beneath an item before the upper grappling jaws may be used to grasp the item. For items that are embedded in the ground, this is often not possible. Also, for irregular items or items that are laying at an angle to the ground, it is often difficult if not impossible to place the bucket securely against an item prior to grasping the item. The sides of the bucket also often impair the ability of the implement to grasp and carry items longer than the width of the bucket.
The weight of the bucket itself in these grappler configurations is also a significant disadvantage. Every utility vehicle has a maximum weight that it can effectively lift, handle and transport. The weight of the bucket must, of course, be included in this maximum weight capacity and, the heavier the bucket, the lower the lifting capacity of the vehicle.
In addition, the bucket often obscures the visibility of the operator, making it difficult for the operator to use the bucket and grappling jaw to grasp and carry certain items.
Grappling jaws with opposing tines or claws that interlock when closed have been developed that attempt to overcome some of these limitations. These implements, often referred to as grapple rakes, utilize a second set of tines or claws in place of the lower bucket to provide opposing claws that are better suited for grasping certain objects. For example, U.S. Pat. No. 6,098,320 discloses grappling jaws useful for dislodging and grasping large stones embedded in the ground. These grappling jaws include a lower set of tines that may be inserted in the ground beneath a stone and an upper set of tines that may then be closed around the stone. Opposing grappling jaws with an upper and lower set of tines are also disclosed in U.S. Pat. Nos. 6,176,531 and 6,601,891.
Although useful for certain tasks, these grapple rakes are not well suited for highly precise grasping tasks or for lifting and carrying irregularly shaped items such as fallen trees and brush. To provide structural stability and strength, the upper and lower sets of claws on these prior art grapple rakes are typically constructed as unified or solid pieces that clamp in opposition on another. When grasping an item of uniform cross section, or material that may be easily crushed between the opposing jaws, these designs are adequate for securing the item.
However, when a solid item to be grasped has a tapered or irregular cross section, one claw may be restricted from closing on the item when the other claw closes on a larger portion of the item, causing the item to be held by only one claw and not the other. In this instance, the item cannot be safely transported without the danger of the item moving and shifting during transport.
To address this problem, grappling implements have been developed with upper fingers that may be closed independently of one another. For example, Bobcat Company offers Industrial Grapple and Industrial Fork Grapple implements with two sets of upper claws that may be closed independently of one another. Worksaver, Inc. also offers a Split-Top Grapple Rake with dual upper grapples that may also be closed independently of one another. Although these implements do provide increased control over bulky and irregularly shaped items, they do not offer the precision and control necessary for many tasks. In particular, these configurations do not provide a grasping implement that can be precisely placed around irregular items or obstructions and easily controlled by the operator for grasping and lifting irregular items.
Such features are especially useful for clearing fallen trees, branches and brush. Clearing such items presents specific challenges for the operator and the construction of the grasping implement. First, operator visibility and precise control are essential for precise placement of the fingers through limbs and branches prior to closing the fingers. Second, high strength of the fingers is essential so that smaller branches and brush may be crushed between the fingers. Third, the hydraulic cylinders and lines must be protected from damage from branches and limbs during operation. Thus, a grappling implement adapted for clearing fallen trees, branches and brush must offer high visibility, precise control, high clamping strength and protection for the hydraulic components.
Accordingly, an object of the present invention is to provide pinching fingers for a tractor, skid steer or the like that may move and grasp independently so that both claws can be used to grasp and safely transport irregularly shaped items such as fallen trees and brush.
An additional object of the present invention is to provide a grasping implement that does not obscure the visibility of the operator and provides precise control so that highly precise grasping operations may be performed.
Also, an object of the present invention is to provide pinching fingers with high clamping strength.
Another object of the present invention is to provide pinching fingers that protect the hydraulic cylinders and lines used to control the fingers.
A further object of the present invention is to provide pinching fingers that are easy to install and remove on a conventional loader or skid steer.
Yet another object of the present invention is to provide pinching fingers that can be quickly interchanged with other implements on a conventional loader or skid steer.
A still further object of the present invention is to provide a pinching fingers attachment with sufficient structural stability and strength to grasp, lift and transport heavy items including logs, trees and other items.
Still another object of the present invention is to provide an improved vehicle with a pinching fingers attachment.
Another object of the present invention is to provide a backhoe with a single set of claws.
A further object of the invention is to provide a loader or skid steer with pinching fingers that are simple and easy to operate.
Finally, an object of the present invention is to provide a pinching fingers attachment that is economical to manufacture, durable and refined in appearance.